1. Field of the Invention
This invention relates to a recovery device used for recovery from unsatisfactory ink discharge of an ink jet recording head, an ink jet printer provided with the recovery device, and an electronic desk calculator provided with the printer.
2. Related Background Art
In an ink jet printer provided with an ink jet recording head, supply of ink from an ink chamber storing the ink therein to a discharge port for discharging the ink therethrough is accomplished mostly by the utilization of capillary phenomenon. Therefore, if air remains in the ink chamber and/or an ink passageway and bubbles are created, supply of the ink to the discharge port cannot be smoothly accomplished, and this may sometimes bring about an inconvenience for the ink discharge from the discharge port.
The entry of bubbles into the recording head is particularly remarkable, for example, during the filling of the ink chamber of the recording head with ink, or during the mounting of the recording head in a case where the recording head being used is of the cartridge type, or when vibrations are imparted to the printer or the printer falls and is shocked.
So, when the entry of bubbles into the recording head has occurred, it is necessary to remove such bubbles from the recording head to provide a good ink discharge condition.
Also, in the ink jet recording head, it is sometimes the case that the solvent of the ink evaporates at the ink discharge port to create solidities adhering to the discharge port of bubbles and foreign materials such as dust clog the liquid path to cause unsatisfactory ink discharge including non-discharge of ink.
As a method for recovering from such unsatisfactory ink discharge, there is generally adopted, for example, a method of pressing the ink chamber with the discharge port facing upward and forcing the solidities adhering to the discharge port and the foreign materials in the liquid path out of the discharge port, etc. to thereby remove them.
For example, in a prior-art ink jet printer 611 carried on an electronic desk calculator as shown in FIGS. 1A and 1B of the accompanying drawings, a recording head 612 is formed with a small hole (a pressing small hole) 612a used access an ink reservoir bag member (within which an ink chamber is formed) in the recording head, and a pressing needle 613 may be inserted into the small hole 612a to thereby press the ink reservoir bag member.
That is, means for recovery from unsatisfactory ink discharge in such apparatus comprises a flange-like portion (a cradle) 601a horizontally protruding from an upper cover 601 and formed with a recess 601e, and an upright pressing needle 613 having its lower end fixed to the center of the bottom of the recess 601e.
To perform the operation of recovering from the unsatisfactory ink discharge of the recording head as described above, the recording head 612 is first detached from the printer and that portion thereof in which the pressing small hole 612a is formed is gradually fitted into the recess 601e. Thereupon, the recording head 612 assumes its upright state with the discharge port (not shown) facing upward, and the pressing needle 613 provided in the recess 601e is gradually inserted into the pressing small hole 612a in the recording head 612. As the pressing needle 613 is further inserted upward, the ink reservoir bag member (the ink chamber) in the recording head 612 is gradually pressed and the ink is forced up toward the discharge port by the pressure, and the foreign materials, with the ink, are removed from the discharge port. This operation is continued, for example, until the moment when the ink leaks out of the discharge port.
Finally, when the ink has come to leak out of the discharge port, the recording head 612 is raised up and the pressing needle 613 is withdrawn from the pressing small hole 612a, and the recording head 612 is held raised up for a while (so that the leaking ink may not drip). Thereupon, the ink which has leaked out onto the recording head 612 is gradually absorbed from the discharge port into the ink reservoir bag member due to the elastic force of restitution of the ink reservoir bag member.
When the absorption of the ink is completed, the surface tension of the ink in the discharge port portion becomes balanced with the negative pressure in the ink reservoir bag member and therefore, no air enters thereinto and the recording head becomes ready for normal use.
After the operation of recovery from unsatisfactory ink discharge is completed in the manner described above, an ink cartridge is set in the printer.
In the above-described prior-art printer, however, it is necessary that the size and shape of the flange-like portion 601a and the location at which it is installed be set so that a sufficient space for accommodating that portion of the recording head in which the pressing small hole 612a is formed may be provided in the recess 601e in which the pressing needle 613 is provided and moreover, during the pressing of the ink chamber, an effective operation of recovery from unsatisfactory ink discharge may be accomplished with the recording head remaining upright, for example, so that when any ink leaks out of the discharge port, it will not go into the printer.
However, such reguirements in the design of the flange-like portion 601a are great limitations on the compactness and design of the printer itself, and they are problems that need to be solved for such printer to be carried on various types of instruments such as more compact electronic desk calculators or instruments which are higher in function and fashionableness.
Moreover, the pressing needle 613 is always upright and therefore, meticulous care must be taken so as not to break the pressing needle 613 when handling the printer and thus, there has been the problem that hindrances sometimes occur to the operability of the printer.